Single vessel blast furnace and steel making/gasifying apparatus and process

ABSTRACT

A blast furnace for use in an apparatus such as a steel making apparatus or a gasifier includes a crucible having a tap hole for discharging molten slag therefrom. The furnace includes a lance for introducing fuel and oxygen into the crucible and instrumentation for continuously measuring characteristics of molten slag discharged through the tap hole to control processing of fuel and oxygen in the crucible. In one application, a single vessel steel-making apparatus includes a crucible having a first tap hole for discharging molten slag therefrom and a second tap hole for discharging molten steel therefrom and includes an additional lance for introducing a carbon reducing oxygen blast into a mass of molten steel in the crucible.

CROSS REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/629,486, filed Nov. 19, 2004 and U.S. Provisional Application No.60/635,117, filed Dec. 10, 2004.

BACKGROUND OF THE INVENTION

This invention relates to the control of continuous and directiron-making or gasification using pulverized or finely ground coal, ironore (where applicable) and other materials and unique sensors andcomputer control techniques and methods in a continuous smelting processsuch that through the judicious application of these specialized sensorsand techniques that this present invention does not require people tointerface with the process directly except by keeping the lock hoppersfull of previously pre-heated (not shown) feed ingredients, and two lockhoppers are used for each ingredient to insure continuous andinterrupted feeding of materials.

Much of present steel making is manually controlled with manual samplingof steel quality, manual control of molten levels within the furnace,long time lags, high expense of apparatus since coke, recuperator,peepholes, excessive labor and reduced productivity result. Currentgasification apparatuses are not well suited to recovery of materials,including metal recovery from the coal or carbon gasified.

DESCRIPTION OF RELATED ART

A related invention, while nowhere as descriptive and fully controlledas the present invention, is the Hlsmelt process. There are no specificmeans or ways specified to control the Hlsmelt steel making process asoutlined in U.S. Pat. No. 6,626,977. And it is not necessarilyadvantageous to feed mix materials with multiple lances immersed in themolten steel such as Hlsmelt teaches, which is therefore more cumbersomeand expensive to build and maintain since material feed and blast can bemore simply done as outlined in U.S. Pat. No. 4,639,269, which thepresent invention greatly improves upon, and adapts to steel making.What is lacking in U.S. Pat. No. 6,626,977 to achieve inexpensive andhighly productive continuous direct steel making technology that is costeffective are means to measure and control the process, which presentlyis left up to the design and construction engineers and not specified inU.S. Pat. No. 6,626,977. These are complex matters not practiced in theart, and this invention shows how to do this with a very high degree ofspecificity for process control and optimization so necessary to producelow grade steel quality directly from a single smelting/steel-makingcrucible within the furnace process while minimizing labor, capital andmaximizing productivity income opportunities simultaneously. Similarly,gasifiers do not practice the art of a molten slag pools or controlthereof of sufficient depth to recover metals that sink to the base forrecovery or that more easily makes a saleable aggregate that suchpractice can make possible. The control over the gasification and steelmaking process is also greatly enhanced as described herein.

SUMMARY OF THE INVENTION

A direct and continuous controlled smelting and low-grade steel makingprocess or coal or carbon gasification which involves blasting a mixtureof pulverized ore (but not if just a gasifier), coal, and a fluxmixture(s) through a concentric water cooled downward lance close into amolten slag, with ore mix flowing between the outer cooled shell andinner core air blast tube which expels air/oxygen mixture at highvelocity onto the top of the molten slag and steel layers, and to makesteel with air/oxygen blast under the molten layer from the base of thecrucible distributed evenly through a fine bubbling diffuser mountedwithin the crucible floor so as to reduce carbon in the molten iron,means to separately meter ore mix ingredients from lock hoppers withbubble-tight valves to prevent gas from flowing back though the hoppers,and with in-line mixer before entering the concentric lance, and withCO2 /CO and temperature exit gas measurement instrument with exit gasconcentric pipes allowing heating of inlet air/oxygen blast, includingcirculating such air/oxygen within the top metal plenum of the furnacewith inner shell made of high temperature steel alloys enablingachievement of 1200 F air/oxygen blast, and it has slag and low-gradesteel outlet trough with above laser spectrometer measurements todetermine chemical composition of both flows, and crucible verticalscanning nuclear gage of molten steel, slag and fresh mix layers todetermine their vertical profile density and relative depths andplacements, all this instrumentation so as to combine and with suitablecomputer control and optimizing algorithms and software to properlycontrol preheated ore mix feed rate and composition, levels of molteniron, air/oxygen blast rates, and to manipulate molten levels usingeither an actuated tap hole plug controller or refrigerant to freeze aportion of the tap hole exit area or eddy current inducing forces toslow down steel exit flow so as to provide reliable backup methods ofslag and steel flows so as to accurately maintain molten steel and slaglevel set points within the crucible, all to produce a quality low-gradesteel output with proper carbon, sulfur and potassium contents to themaximum practical extent so as to optimize steel making within onevessel in terms of quality and production requirements and to maximizethe overall cost effectiveness of process of smelting and steel-makingor gasification.

Specifically, one process of the present invention includes thefollowing:

At least 2 lock hoppers for each ingredient of combination of similaringredients such as pulverized coal, ore, and fluxes (mix) are used toguarantee their continuous feed. These lock hoppers have speciallydesigned variable speed flotation helical undercutting rotors toundercut and simultaneously unload and regulate feeds, after calibrationwith rotary rpm, as necessary to maximize production consistent withsteel desired quality, generally carbon content, and more than one fluxmaterial lock hoppers (one set is shown) may be added to control sulfurand phosphorous content of the final low-grade output. The invention isnot intended to make a high grade steel which would take place infurther downstream operations not described here. These lock hoperswould use bubble tight high-temperature valves on their inlet and outletthat are capable of hundreds of thousands of operations, such a valvemade by Macawber Engineering Incorporated, which are especially suitedto this application since it's necessary that no air blast can pass upinto the air or nitrogen purged lock hoppers (to avoid possible dustexplosions in the pulverized coal lock hoppers when filling, it may bedesirable to nitrogen purge these hoppers and all other hoppers aswell).

An in-line mixer at the start of the chute or pipe that feeds into theconcentric lane entering through the center top of the furnace. Allingredients converge by gravity flow or other means at this point forgravity flow into the slag and molten slag mass for smelting into ironand eventual conversion into low grade steel as the ingredients worktheir way into the discharge tap hole on the center floor of thecrucible.

From the in-line mixer, a vertical pipe with an enlarged section wherethe water cooled lance section begins and where the hot air/oxygenenters through the outer cooled enlarged shell into the center air blasttube, whereby such cooled lance enlargement is sufficient for all feedmaterials to flow at maximum rates easily passing by the narrow verticalrectangular tube penetrating into the lance outer core on one side tofeed the center circular round tube of the lance with hot blastair/oxygen.

A concentric lance section with cooled outer upper furnace ceiling closeto the molten ash level, such gap between end of lance and top of moltenslag made adjustable by the control set point level of the molten ash,with ore mix flowing between the other cooled shell and inner tube withthe tube shorter than the cooled outer shell, or in the case ofgasification, radial water or steam spraying to create gasificationreactions, at the end where ore mix and air/oxygen impinge into themolten mass inside the furnace, whereby such hot air tube is shorter andinside the outer shell sufficiently to create a venturi or suctioneffect to pull the ore mix down the lance, and whereby the high velocityof the air/oxygen achieves thorough mixing and combustion of coal tosmelt the ore and relying on then remaining molten slag and steel tofinish smelting and conversion into iron at the upper region of themolten iron layer while impinging at sufficient velocity to push asidemolten slag. In the case of gasification, preheating ingredients andlast oxygen is not as critical as with steal making where smeltingoperations are involved whereby the whole of the gasification vessel canbe refractory lined and cyclone cleaner made contiguous with thegasifying vessel.

The upper shell of the furnace with insulated outer layer and hightemperature steel alloy inner layer allow the inner layer to finishheating the pre-heated air/oxygen blast to 1200 F, designed withsufficient inner surface area of the exposed upper furnace to achievethese final blast temperatures at full load steel flow given that suchallow inner steel alloy surfaces may be coated with ceramic or otherhigh temperature material to additionally protect the inner steel shellfrom corrosion and provide sufficient insulating layer to preventexcessive temperature from melting or excessively lowering the strengthof this steel alloy. However, in any event, this upper furnace steelsection would be supported above by a frame (not shown) surrounding thefurnace on its sides as necessary.

Concentric exhaust high temperature allows pipes for exit gases to beceramic coated as necessary for corrosion protection and excessivetemperatures, such that the air/oxygen mixture flowing in the outerconcentric space pre-heats the incoming air/oxygen blast before itcirculates around the top shroud of the furnace for final temperatureincrease and entrance into the center air tube of the lance, whereby theinner exhaust gas tube section at the exits into a co-generating boiler(not shown) or other energy recovery system with comprehensive emissionabatement additions, generally a high efficiency power boiler, has acombination CO2, CO and temperature measurement instrument mounted thereto measure the character of the exhaust gas for computer controloptimization purposes of the process.

A refractory lined and insulated (insulation not shown) crucible belowthe upper air cooled metal portion of the furnace has a center bottomtap hole for finished low grade steel and a tap hole some distance abovethe floor on the side wall of the refractory crucible to accommodateslag removal, the height of this slag hole would be determined bydesign. For example, if for basic steel making 600 tons were to bemaintained in the crucible, the slag tap hole may be as high as 6-7feet. It has a ceramic fine air/oxygen bubbler diffuser of sufficientdiameter and flow to cause adequate carbon reduction in the iron in thelower section of the molten iron layer to convert smelted iron tolow-grade quality steel, whereby such steel (or recovered metals as ingasification) flows down through an open center hole of this diffuserand tap hole passage is a ceramic pipe which turns at right angles tolet out steel from a side wall tap hole below the crucible floor butabove the lower steel shell of the furnace and imbedded within therefractory, and such ceramic passage hole pipe is a magnetic inducingcoil or plates to produce counter forces to steel flow to assist in thecontrol of steel outflow for crucible molten level control purposes.

Also to further assist in steel or molten flow control, the outer steeltap hole ceramic pipe can be wrapped with refrigeration coils throughwhich refrigerant at various temperatures and flow rates can be used tosolidify steel to form smaller or larger openings tap hole openings tocontrol the flow of molten steel out. Or, further molten steel and slagflow control reliability is achieved with an outer tap hole tapered plugusually used to control such molten steel flows with suitable actuator,and readily available in the art. Or, the bottom hole can be arranged touse a tapered plug valve for flow control.

These flows of slag and steel into a trough of sufficient volume andweir dam sufficiently higher than the tap hole to cover the tap holesuch that the velocity of the flow does not overly agitate flow over theweir for weir vertical level measurement purposes. A radar or sound typelevel measurement instrument locate above the weir can accuratelydetermine the flow height in the weir notch to measure the volume ofslag or steel flowing over the weirs.

A laser spectrometer above the troughs to measure steel and slagchemical properties to judge steel quality and slag carbon losses, suchinformation manipulated by the degree of air/oxygen blasts, mass flowrates through the crucible, feed rates of all individual ingredients,including combustion of coal as measured by a combined CO2, CO, andtemperature sensor mounted on the final exhaust gas pipe or other knownmeans necessary to control these parameters. Or laser spectrometry raysshooting across the combustion area also be used, both for steel andgasification.

A vertical scanning nuclear level gage means to send the usual highenergy beam through a uniform vertical section of the crucible, ineffect a chord of the crucible measuring only a segments chord length tominimize the nuclear penetrating emission required, and such cruciblemay be so arranged in shape as to be elliptical to make the amount ofthickness of the chord further minimized, and the full vertical heightof the refractory lined crucible designed to be vertically uniform, withsuitable detector on the other side to continuously scan into the totaldesign depth of the molten slag, steel, and fresh ingredients depthwithin the crucible so as to determine density profile to control moltensteel and ash and fresh ingredient levels or thickness by control ofoutflow molten steel rate, slag flow rate, ore mix inflow rate to insurefresh material are not accumulating above the slag (is being smelted atan adequate rate) which might require more blast or a higher ratio ofcoal in the final mix admitted into the furnace, or that the slag andmolten steel levels are being properly maintained. The computeralgorithms to control these variables can be created by those skilled inthe art of steel making and are discussed further below. Thus with thislevel measurement and other measurements noted, the direct andcontinuous steel making processes is fully automated and optimized.

Such a crucible arrangement can also be advantageously used to createand control a molten ash system under the hoppers of municipal solidwaste burning or low temperature coal gasification systems, coalboilers, or any system where it's desirable to create molten ash so asto minimize its carbon content, except in this instance the verticalscanning nuclear gage and outflow tap hole level control plug/actuatorcombination etc. are used to control, the molten level of ash, and thata level of fresh ash material is maintained atop this molten ash layer,and that water cooled lance is inserted at an angle from the side of thecrucible to inject pulverized coal or other inexpensive polarized fuelplus air or oxygen with excess air needed to combust the fuel,preferably an enhanced air/oxygen mixture is used as an oxidant toassure supply adequately high temperatures as necessary to maintain themolten ash state and control the thickness of the insulating ash layer.In this case, the computer gives out two primary control signals, onefor molten ash level control by controlling the tap hole flow, and oneto regulate the amount of pulverized coal energy entering the lance tomaintain a suitable insulating ash level above the molten ash, wherebyboth these level conditions inside the crucible are measured by thescanning nuclear gage.

In the case of making steel, control valve means to adjust air/oxygenblast rates into the top lance and bottom fine bubble diffuser andoptimizing algorithms to computer control the whole furnace process asfollows in items A-H below:

A. If more production is needed, the computer looks to increase steeland slag levels and if it can, does so to increase mass in the systemand then adjusts to a higher steel and slag flows out with the scanningnuclear gage input enabling precise levels and thickness of iron andslag to be maintained within the furnace, and if final steel carbon isincreasing per spectrometer measurements, it increases bubblingair/oxygen flows. If CO is excessive, it increases the hot air/oxygenblast from the lance.

B. If steel carbon content too high, the computer increases bubblingair/oxygen, and if that does not correct it, increases the lanceair/oxygen blast as well. If it is still too high or reducing atmospherein the furnace is getting too low (as evidenced by decreasing COmeasurement), the ore mix feed is reduced to bring the carbon reducingcapability of the diffuser into it's acceptable range of capability.

C. For furnace molten iron level for any given ore feed rate (productionset point), the nuclear scanning gage enables furnace iron level to beadjusted by the steel outlet tap hole plug position or refrigeranttemperature or flow rate, eddy inducing restricting forces whichevermeans of flow control are used or necessary to be used. All three can bedesigned to operate in staggered way; eddy current first, refrigerantflow second, and use of the tapered plug force or position third.

D. Or for any given production level, the nuclear scanning gage enablesslag level to be adjusted by the slag outlet tap hole plug position orforce level. If exit gas CO level is too low (thus CO2 level too high)this indicates the air/oxygen lance blast is too high for the productionlevel set, therefore blast is reduced and if, however, fresh feed levelor slag thickness continues to accumulate beyond a safe or acceptablelevel, then either blast has to increase, or ore feed has to decrease,and iron level control follows from these changes.

E. If the steel carbon level is acceptable, but other steel chemicalparameters are too high or too low the only remedy is a change of theore mixture by adjusting lock hopper discharge rates. It will take along time constant for these changes to show up in the final steel sincethere can be up to 6 hours of steel capacity contained within thecrucible for basic steel manufacturing operations (calcium carbonateused as flux).

F. The laser spectrometer on slag monitors it for iron and carboncontent indicating an ore mix change may be needed or that more lanceblast is needed. It may be desirable to let out-of-limit carbonconditions prevail in the slag if it is the most cost effectiveoperation. The computer can be capable of calculating the costconsequences of various operation modes.

G. Since it's almost always desired to evolve to maximum possibleproduction capability of the furnace, the computer can always be set toa evolutionary operations standard of maximum production, say asdetermined by an upper level carbon content of the final steel or ironor slag. In this instance, the computer will slowly ramp up input or mixfeed rate and adjust crucible molten slag and iron levels to maximizeproduction. Maximum possible levels of slag and iron will be determinedover time. Increasing top air/oxygen lance blast and bubbling O2 ratesshould maximize steel production until a limiting condition is reached(say excessive carbon in the final output steel, then the computer willback down production to within a safe production level such that thereis a measure of control over the process using the parameters of CO2/CO, final spectrometer measurements of steel and slag, furnace iron andslag level or thickness, air blast, air/oxygen bubbling rate, or ore mixcomposition, all automatically adjusted by the computer control systemalgorithm determinations.

H. Steel and slag weir flows (weir levels) are measured since theyindicate production levels of actual steel and slag and they can alsoindicate an upper limit has been reached or that there are flow moltensteel or slag flow control problems. For example, if the plug opens thetap hole more but no increased flow is noted in either slag or steel,then ether the flow control actuating methods are failing and computerhistorical data can immediately enable the computer algorithm to alarm,and determine what the operator should check first.

Thus, it can be seen that this invention teaches a very advanced methodof continuous steel making and/or gasification and uses the most moderncombination of instruments and sensors to accomplish this, and itteaches a unique arrangement of equipment and process to avoid the needfor coke and expensive recuperator to preheat air/oxygen blast to propertemperatures, and finally, optimization algorithms are suggested suchthat those skilled in the computer programming arts in combination withsteel process engineer experts in acid or basic steel making processescould enable such software to take advantage of with the instrumentsignals provide to gain precise and accurate control over the processincluding ingredient mix ratios and all material flows to optimize steeloutflow rates with quality for maximum economic advantage with a minimumof labor input and capital cost.

The present invention and its advantages over the prior art will be morereadily understood upon reading the following detailed description andthe appended claims with reference to the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

The subject matter that is regarded as the invention is particularlypointed out and distinctly claimed in the concluding part of thespecification. The invention, however, may be best understood byreference to the following description taken in conjunction with theaccompanying drawing figures in which:

FIG. 1 is a vertical schematic section of one embodiment of the presentinvention.

FIG. 2 is a vertical schematic section of another embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings wherein identical reference numerals denotethe same elements throughout the various views, FIG. 1 shows a directsmelting iron and steel making apparatus. While an iron and steel makingapparatus is shown here by way of example, the present invention relatesto any type of apparatus that produces a molten by-product, such asmolten slag or ash, including, but not limited to, iron or steel makingapparatuses, solid waste, coal and other types of gasifiers,waste-to-energy boilers, and coal boilers.

Three lock hoppers 1, 2, and 3 are shown and there would be an identicalhopper behind each one so as to allow continuous flow of materials fromthe one in front or behind. That is, while one of the lock hoppers ofeach pair is operating, the other lock hopper is being filled. Each lockhopper is fed pulverized materials to the extent practical for coal 4,ore 5, and fluxes 6 through conveyors (not shown) to re-fill the hoppersas determined by level sensors 7′. In such a fill cycle, the hopperbeing filled is not operating, its outlet valve 8 is closed, its fillvalve 7 is open, and the appropriate material is entering the hopper.

Each hopper has an unloader/feeder unit 10 such as one comprised of aloose spline drive inward floating helical plate (not shown) withrotating cap 11 preventing free fall of material 12 in the center outlethole, not shown, whereby material is made to flow at a rate determinedby the speed of drive motor 13. Such an unloader feeder is describedmore fully in U.S. Pat. No. 4,659,340, issued Apr. 21, 1987 to Lloyd E.Weaver and incorporated herein by reference in its entirety.Alternatively, there are other commercial versions of such technologythat can be used to advantage in this invention.

As a gasifier, because it's desirable to keep nitrogen out of thegasification reactions to avoid noxious nitrogen based compounds, oncefilled, it's desirable to close valves 7 and 8 and evacuate the chamberby vacuum pumps (not shown) and purge with an non-reactive or inert gasto repressurizing (apparatus not shown) so as to prevent undesirablegasification reactions when oxidizing reactions take pace from pureoxygen addition 20 through inner lance 19 tube 30.

Also, in feeding coal and flux or any materials to gasifiers, it shouldbe a dry and finely ground material, but it does not have to be a finepowder, as pure oxygen is highly reactive with carbon under suchcircumstances of process as depicted in the invention. Therefore, justas in times past coal was prepared and stored in large bins prior tofeeding to boiler burners, a better practice for this invention would beto adequately dry and prepare the granular material to be gasified orutilized when such surge bins (not shown) are used before feeding coalto the lock hoppers 1, 2, or 3 or however many are required to get thechemical reactions desired, prior to applying vacuum andre-pressurization of the hopers and subsequent feeding the mixedmaterials 18 to the gasification or reactive chamber respectively.

Materials 4′, 5′, 6′ (coal, ore, and fluxes respectively) flow bygravity through chutes all to combine into mixed flow 18 by mixer 15outputting into pipe 16, whereby the flow 18 splits to flow around innerlance air/oxygen tube 30. Pipe 16 which can be as large as twenty-fourinches in diameter or more for furnaces with 800,000 tons per year ofsteel producing ability. Also, as shown, pipe 16 is shown to enlarge topipe diameter 17 to allow mix 18 to freely bypass into concentric lance19. At this point, the shell 17 and lance 19, now larger than pipediameter 16 as appropriate, have cooled outer shells.

In describing the upper furnace area, starting with air/oxygen blast 20,passing through flow control valve 21, air enters concentric pipeassembly 22 and 23 where 22 is the other shell and 23 is the hot inneralloy pipe for furnace exit gases 24. It should be noted here that theterms “air” and “oxygen” can be used interchangeably here and the eitherterm, whether used alone or together, refers to air, pure oxygen or anyother oxygen-containing substance. The pipe assembly is close coupled toa heat recovery or boiler apparatus, not shown but the inner pipe 22 hasa combination CO2, CO, and temperature sensing unit 25 mounted at theend for purposes of assisting in computer (not shown) control the blastfurnace of FIG. 1. It is not intended that the length of the pipeassembly 22 and 23 must pre-heat the incoming air 20 to the full extentneeded as that is accomplished in the metal upper furnace sectioncomprised of inner and outer shells 27 and 28 respectively. To completethe full pre-heat for inner lance 30, that is heating air/oxygen mix 20to the 1200 F. or so needed by the furnace, hot furnace exhaust gases 26pass by inner furnace shell 27 and the outer shell 28, which togetherform the plenum for this flow, to pre-heat 20 as hot final blastair/oxygen 29 whereby this plenum so formed is baffled so 20 takes thelongest path as final heated air/oxygen 29 to enter the lance 19 throughvertically narrow rectangular metal passage 18′ passing through thecooled shell 17, and down into the center tube 30 of outer cooled lance19. The air/oxygen blast 31 impinges into the molten slag 32. Materialmix 18 divides around the inner lance tube 30 as shown, and passes downthrough the concentric opening by gravity to impinge into the depressionof the molten slag 32 created by the force of air/oxygen blast 31.Typically about 10 psig of air pressure would be used to create the highvelocity of the air/oxygen blast 31 needed, which is well known by thoseskilled in the art and thus enables determination of the final innerdiameter of inner lance tube 30. Gas 26 passes around cooled and ceramiccoated baffle 33 which helps to remove particulate before hot exhaustgases 26 leave the furnace through top furnace plenum opening 34 toenter inner exhaust high temperature alloy pipe 23, which may need to beceramic lined to withstand corrosion and high temperature effects.

The lower furnace area is comprised of refractory lined crucible withbase 35 and outer shell 35′ and straight vertical inner refractory walls36 and tapered in with section 37 to the inner upper furnace shell 27.The inner diameter of this crucible could be as large as 20 feet insidediameter to accommodate say 600 tons of steel maintained in the furnacefor basic steel operations for an 800,000 tons per year furnace. Tocontrol upper molten ash level 38 and molten steel level 39, a scanningnuclear gage is used which is a well known measurement technology and isgenerally comprised of a scanning source 40 and corresponding scanningdetector 41. These would not generally scan through the center of thediameter but rather off to one side scanning a chord of minimum suitablelength for suitable nuclear ray penetration through the furnace andfurnace mass to detect the full range of slag 38 and steel 39 and upperfresh feed mass thickness 42 to the extent that it exists. This signalis feed into a computer programmed to show a complete vertical densityprofile of the vertical height measured which can be used to makedecisions of inflows and outflows to the furnace to be discussed below.

The upper layer of the molten steel molten mass 43 is expected to bewhat would be considered as smelted iron and the lower level of 43 to below-grade steel created by the carbon reducing action of air/oxygenblast 44 controlled by valve 45 which passes into the base of thecrucible 35 through fine bubbling diffuser 46 and up though the mass ofmolten steel and slag depicted as bubble streams 47.

The low grade steel 48 exits the base 35 through ceramic pipe passageway 49 which through most of its length is surrounded by eddy currentinducing forces coil or plate(s) 50 which can be activated byelectricity so as to act as a countervailing force to slow the exit flowof steel 48 through passage way 49. The outer tap hole area 51 of pipe49 is surrounded by refrigerated coil 52 which can have cooled fluids atvarious flow rates and temperatures, adjusted by computer control basedon nuclear sensor 40, 41, to cause the exit tap hole 51 to shrink insize at coil 52 so as to assist in control of steel 48 flow out tomaintain molten steel level 39. Or, the computer can activate theactuator 53, well known in the art, which actuates submerged taperedplug 54 away from or towards tap hole 51 to increase or decrease outflow as required, thereby acting as a further backup molten steel level39 control method.

Having described this level control process of molten steel and slag,and referring to the nuclear vertical scanning gage 40, 41 above, thissame process can be used to advantageously create and control a moltenash making process which is advantageous to reduce the volume of ashfrom ash hoppers of waste to energy boilers, coal boilers,low-temperature gasifiers, one known as PCPG, and to make this ashsuitable for recycling in road aggregate and the like, and this wouldwork as follows: in this instance, there would be a source of excessair/oxygen mixture and pulverized coal or any low-cost energy fuelinjected through cooled inclined lance 55 shown as a dotted lines inFIG. 1 (shown immersed into molten steel 43), but in this instance itwould be molten ash level that would be made and controlled, not steel.The iron slag 32, 38 representing non-molten ash would then beessentially level (no upper vertical lance 19 is used) and the levels32, 38 would correspond to a layer of insulating ash over the moltenash. With the scanning nuclear gage measuring the vertical densityprofile of the two layers of non-molten ash floating on the molten ash,the computer can control both the outflow rate of molten ash to controlits level, and the amount of energy blast of pulverized coal and excessair/oxygen through lance 55 (preferable oxygen enhanced air mixture tocause intense burn temperatures from the pulverized coal) so as tomaintain adequate temperatures for melting ash to control ash thickness,whereby more ash flow into the crucible would require more energy blastthrough cooled lance 55.

To complete the description of the outflow control of the molten steeland slag process, steel passes out though tap hole 51 into trough 56which has sufficient volume and height to allow steel level 57 to extendsufficiently in level above tap hole 51 such that the steel flow 58 overnotched weir 58′ is not unduly agitated such that non-contacting sonicor radar level sensor 59′ can accurately measure level 57 for accuratesteel volume flow measurement. In addition, above the trough steel level57 is mounted laser spectrometer measurement unit 59 which is used tofeed the control computer a chemical analysis of the steel such as iron,carbon, sulfur, and potassium and other elements to insure adequatesteel quality is being maintained.

Similar methods are used to control the molten slag flow andcharacteristics such as carbon content including such previouslydescribed elements as eddy current coil 60, refrigerant coil 60′, taphole 61, plug controller 62, tapered plug 63, trough 64, weir 65, troughlevel 66, weir notch level sensor 67 and laser spectrometer 68 tomaintain slag flow 69 to control slag levels 32, 38.

To begin operations of the furnace, molten steel would be added to thecrucible though an upper furnace opening (not shown), and then the hotblast 31 would commence in conjunction with the feed 18 driven by blast31 into the slag as 31′. The computer would be determining the amount ofCO2, CO, and temperature of the final exit gas 24 and begin to adjustfeed rate 18, steel and slag flows 58 and 69 respectively and startingthe adjustments of mix 18 consentient ratios or rates depending onspectroscopic measurements 59 and 68. But because there is such a longtime constant for turnover of steel 43 within the crucible, about 6hours, previous data and experience in steel operations contained withinthe computer data base, plus known experience and nuances about steelmaking programmed into the computer, enables quite accurate initialconditions for all the control variables to be set such as pulverizedcoal, flux, and ore ratios to the total mix flow 18 and what blast 31 isappropriate for what total feed mix flow 18 selected. The finalmeasurements of the spectrometers and outlet gas 24, of CO2, CO, andtemperature and other gases will enable to computer to bring the wholeprocess under control and then fine tune the process for best steelquality consistent with carbon losses in the molten ash and neededproduction level.

Some examples follow of how the computer (not shown) control algorithmswould be set up:

1. If more production is needed the computer looks to see if it canincrease steel and slag levels 32 and 39 and if it can, does so toincrease the steel 43 and slag masses in the crucible, and then itadjusts to a higher steel and slag flows 58 and 69 out with the verticalscanning nuclear gage 40, 41 that determines the crucible vertical massdensity profile enabling precise levels and thickness of iron and slagto be maintained within the furnaces. And if final carbon is increasingper spectrometer measurements 59, it increases bubbling air/oxygen flow44 and if CO is increasing too much, it increases the hot air/oxygenblast 20, 31 blast from above which is increased as ore mix feed 18increases.

2. If the final steel 58 carbon content too high the computer increasesbubbling air/oxygen 44, and if that does not correct it, increases aboveair/oxygen blast 20, 31 as well, if it is still too high or reducingatmosphere in the furnace is getting too low (as evidenced by decreasingCO measurement 25), ore mix feed 18 is reduced to bring the carbonreducing capability of the diffuser into it's acceptable range ofcapability.

3. For furnace molten iron level, for any given ore mix 18 feed rate(production set point), the vertical nuclear scanning gage 40, 41enables furnace iron level 39 to be adjusted by the steel outlet taphole plug position 54 or refrigerant 52 temperature or flow rate (notshown), or increased eddy currents to slow steel flow through 50,whichever means of flow control can be used to best advantage.

4. If CO level as measured by 25 is too low (thus CO2 level too high)this indicates the air/oxygen lance blast 20, 31 is too high for theproduction level set, therefore blast 20, 31 is reduced and if, however,fresh feed level or slag level 32,38 continues to accumulate beyond asafe or acceptable level like become too close to the lance 19, theneither blast 20, 31 has to increase, or ore feed mix rate 18 bydecreasing the unloader motor 13 speeds have to decrease, and iron level39 control follows from these changes by action of the nuclear gagecombination 40, 41 and flow control measures mentioned previously. Morecoal feed 4′ percentage may also be needed.

5. If the steel carbon level is acceptable as measure by steel laserspectrometer 59, but other steel chemical parameters are too high or toolow, a remedy may be a change of the flux 6 mixture and or it's rate ofaddition. Because there may be up to 6 hours of steel production 43retained in the crucible for basic processes, it will take a long timefor these changes to show up in the final steel 58, but it is stillcapable of automatic control and optimization by the computer since thecomputer clock can wait these intervals to check final results from thespectrometers.

6. The laser spectrometer 68 use on slag monitors slag for iron andcarbon content indicating an ore mix 18 ratio change may be needed orthat production can be increased or must be reduced or top blast 20, 31changed to reduce this carbon content. Or it may be desirable to let outof limit conditions for slag carbon content prevail to achieve theproduction level desired. Those skilled in the art of steel making willenable the computer programmer to fine tune the logic to optimallycontrol the process.

7. Since it's almost always desired to evolve to maximum possible steel58 production capability of the furnace, the computer can always be setto a evolutionary operations standard of maximum production say asdetermined by an upper level steel 58 carbon content. In this instance,the computer will slowly ramp up input feed 18 and adjust levels tohigher slag 38 and steel mass level 39 in the furnace (maximum possiblelevels will be determined over time or as observed through hightemperature peep holes in the furnace walls) while increasing top 20, 31blast and bubbling blast 44 until an upper limit of any one of theseparameters is reached such it's then known steel 58 carbon content willstart to rise, then the computer will back down production to within asafe production level such that there is a measure of control over theprocess using the parameters of CO2/CO, final spectrometer measurementsof steel 58 and slag 69, furnace iron and slag level or thickness 39 and32, 38 respectively, air/oxygen blast 20, 31, air/oxygen bubbling rate44, or ore mix 18 composition and flow rate.

8. Steel and slag weir notch flow levels 57 and 66 respectively aremeasured since they indicate production levels of actual steel 58 andslag 69 which can indicate an upper limit has been reached or that flowcontrols are malfunctioning. For example, if the plug opens the tap holemore but no increased flow is noted in either slag 69 or steel 58, theneither the tap hole is too small, the plug is malfunctioning, or a limithas been reached, and computer historical data can immediately enablethe computer algorithm to manage a determination and alarm output whichthe operator then evaluates. All of the various sensor measurements suchas CO2/CO/temrpature 25, nuclear gage 40, 41, spectrometers 59 and 68,weir level sensors 59′ and 67 can be programmed to alarm if extremes intheir condition are reached.

Slag flow 69 would flow to a water quenching recycling operation to makeaggregate from the slag, and steel flow 58 would go on to finishingoperations or to other vessels to enhance steel quality for morespecialized applications.

Referring now to FIG. 2 a second embodiment of a direct smelting ironand steel making apparatus is shown. As before, an iron and steel makingapparatus is shown by way of example, and it should be noted that thepresent invention relates to any type of apparatus that produces amolten by-product, such as molten slag or ash, including, but notlimited to, iron or steel making apparatuses, solid waste, coal andother types of gasifiers, waste-to-energy boilers, and coal boilers.Because the apparatus of the second embodiment is similar to the firstembodiment in many aspects, identical elements will not be describedagain here.

The apparatus of the second embodiment differs from that of the firstembodiment in that gas 26, whether from steel making or gasification,passes into a ceramic cyclone 33 to remove particulate matter of slagand carbon that melts and runs down into a cyclone leg 33′ before hotexhaust gases 26 leave the furnace through top furnace plenum opening 34to enter inner exhaust high temperature alloy pipe 23, which may beceramic lined to withstand corrosion and high temperature effects. Also,cyclone 33 doesn't necessarily have to be inside the gasifier sincerefractory lined cyclones are routinely placed outside enclosed in arefractory lined and insulated steel vessel. With this outsidecontiguous approach to the hot cyclone operation, the cyclone should bevery well insulated refractory, and the leg 33′ contiguous outsideequivalent is brought back into the vessel and immersed in the moltenslag to seal off the cone base. Preferably, the cyclone 33 would bebuilt inside the vessel from ceramic parts, but that may not bepractical with present ceramics parts technology for large systems,whereby for large systems, the ceramic lined steel shell contiguousoutside cyclone noted above would be used. As noted, molten rejects (notspecifically identified) of cyclone 33 run down eject leg 33′ inserteddeep enough into molten slag layer 38 which seals off the base of thecyclone so that it will operate. The pressure drop inside the cyclonewill use slag layer 32 to rise up into leg 33′ (not shown). At highpressure drops, this cyclone will capture nearly all the largerparticles in the excite gas stream and the pressure drop to do this canbe made as large as necessary by enlarging the inside depth of theincandescent chamber 33″ as much as necessary to achieve the desiredresult of practically eliminating all entrained flow particulates,including liquid particulate which drains down leg 33′ to become part ofthe molten slag 38 and 32. And to complete gasification reactions if noiron ore is being added but just coal and flux as in gasification, thewater cooled outer steel of the lance would emit the water as 31′ or assteam air both at various elevations around the lance as required andaround the perimeter of the lance so as to thoroughly penetrate theinner depth of the entrained flow space to complete the gasificationreactions to hydrogen and carbon monoxide. The amount of steam or water31′ emitted from periphery nozzles on lance 19 (details not shown) willdepend of the temperature of the reaction desired, whether blast 31 ismostly air or mostly pure oxygen. Regardless of the characteristic ofthe blast 31, better control of either steel or gasification burnreactions can be achieved by actual gas and internal temperaturemeasurements by using steam gas purged (because steam or water vapor iseasily removed from gasification gases) laser spectrometry 28′ andreceiver areas 28″ and shooting laser rays 28′″ across the furnace insector space where there are no obstructions. Gas constituent sensors 25would also be installed as a back-up and calibration check onspectrometer 28′ and 28″. Alternatively, multiple units of laserspectrometer 28′ and 28″ could be used or, they could become correlatedscanning units as depicted by 70 and 70′, scanning apparatus drives arenot shown but they would be outside magnetic devices moving the laseremitter 28′ and sensor 28″ up and down in a correlated manner withinsteam purged casement 70 and 70′ respectively, with such rectangularsteam purged casements made stiff and rugged enough to withstand thehoop stress on outer casement 28, providing and even more accuratepicture of combustion or gasification within the entrained flow spacedepicted by 33″.

Other variations of the present invention are possible, but the previousdescriptions are low cost ways to make the invention for an integratedsteel making operation whereby the apparatus of FIG. 1 or FIG. 2 is usedin conjunction with a sizable power boiler, such boiler having severalother large pulverized coal burners added to enhance profits from poweroperations, while the power boiler fully cleans up the emissions fromsteel making through the boiler's comprehensive emissions reducingapparatus on the boiler stack gases. Thus, the above-describedembodiments are capable of a completely hands-off automatic control overthe steel-making process in a cost effective manner. The presentinvention achieves a minimized capital cost apparatus by beingclose-coupled with co-generation power operations. It doesn't requireexpensive coke to operate, only cost-effective pulverized coal 4,preferably a dry low sulfur coal, nor expensive recuperator usuallyrequired to make the furnace operate by using what heat can be capturedfrom the concentric close-coupling connecting pipes 22, 23 and bydesigning the upper furnace plenum created by 27, 28 so as to fullypre-heat the blast air/oxygen 31 at a minimum capital cost. Thiscompletes the detailed description of the invention such that oneskilled in the arts involved can make and operate this invention.

While specific embodiments of the present invention have been described,it will be apparent to those skilled in the art that variousmodifications thereto can be made without departing from the spirit andscope of the invention as defined in the appended claims.

1. A blast furnace comprising: a crucible having a tap hole fordischarging molten slag therefrom; means for introducing fuel and oxygeninto said crucible; and means for continuously measuring characteristicsof molten slag discharged through said tap hole for controllingprocessing of fuel and oxygen in said crucible.
 2. The blast furnace ofclaim 1 wherein said means for continuously measuring characteristics ofmolten slag discharged through said tap hole includes a trough forcollecting molten slag discharged through said tap hole, said troughincluding a weir, and a level sensor for measuring molten slag level insaid trough.
 3. The blast furnace of claim 2 wherein said means forcontinuously measuring characteristics of molten slag discharged throughsaid tap hole further includes a laser spectrometer for obtaining achemical analysis of said molten slag in said trough.
 4. The blastfurnace of claim 1 further comprising means for detecting molten slaglevel inside of said crucible.
 5. The blast furnace of claim 4 whereinsaid means for detecting molten slag level includes a scanning nucleargage.
 6. The blast furnace of claim 1 further comprising means forcontrolling molten slag flow rate through said tap hole.
 7. The blastfurnace of claim 6 wherein said means for controlling molten slag flowrate includes a refrigeration coil around said tap hole.
 8. The blastfurnace of claim 6 wherein said means for controlling molten slag flowrate includes a moveable tapered plug aligned with said tap hole and anactuator for controlling movement of said tapered plug.
 9. The blastfurnace of claim 6 wherein said means for controlling molten slag flowrate includes eddy current inducing means located adjacent to said taphole.
 10. The blast furnace of claim 1 further comprising means fordischarging hot gas from said furnace.
 11. The blast furnace of claim 10further comprising a cyclone for removing particulate matter from saidhot gas before said hot gas is discharged from said furnace.
 12. Theblast furnace of claim 11 wherein said cyclone is located inside saidfurnace.
 13. The blast furnace of claim 11 wherein said cyclone includesa leg that is immersed in molten slag in said crucible.
 14. The blastfurnace of claim 10 further comprising means for sensing characteristicsof hot gas that is inside or being discharged from said blast furnace.15. A single vessel steel-making apparatus comprising: a crucible havinga first tap hole for discharging molten slag therefrom and a second taphole for discharging molten steel therefrom; means for introducing fueland oxygen into said crucible; and means for introducing a carbonreducing oxygen blast into a mass of molten steel in said crucible. 16.The steel-making apparatus of claim 15 further comprising means fordetecting molten steel and molten slag levels inside of said crucible.17. The steel-making apparatus of claim 16 wherein said means fordetecting molten steel and molten slag levels includes a scanningnuclear gage.
 18. A process comprising: introducing fuel and oxygen intoa crucible; combusting said fuel in said crucible to produce moltenslag; discharging molten slag through a tap hole formed in saidcrucible; and continuously measuring characteristics of molten slagdischarged through said tap hole for controlling processing of fuel andoxygen in said crucible.
 19. The process of claim 18 wherein saidprocess is a gasification process.
 20. The process of claim 18 whereinsaid process is a gasification process.